Since olefin polymers such as polypropylene and polyethylene are excellent in mechanical properties and chemical resistance, and excellent in balance between those properties and economical efficiency, they have been widely used in various fields such as a packaging field. These olefin polymers have conventionally been produced by polymerizing an olefin using a conventional type solid catalyst (multi-site catalyst), which combines a solid catalyst component obtained by using a metal compound of the Group IV such as titanium trichloride or titanium tetrachloride, with a metal compound of the Group 13 represented by an organoaluminum compound.
However, as a catalyst providing addition polymers having less stickiness and more excellent strength than those produced by the conventional catalyst, a so-called single site catalyst prepared by combining a catalyst component such as a metallocene complex or half metallocene complex with a co-catalyst component for activation such as an aluminoxane, and tri(n-butyl)ammonium tetrakis(pentafluorophenyl)borate, was proposed and with respect to the single site catalyst, improvements for using it in an industrial scale have been studied (e.g. JP 58-19309 A, U.S. Pat. Nos. 5,621,126, 5,153,157).
Further, recently, a compound prepared by contacting diethylzinc and pentafluorophenol has been developed as a co-catalyst component for activation, and a catalyst prepared by contacting said co-catalyst component with the metallocene complex has been proposed as a high activity catalyst (e.g. U.S. Pat. No. 6,586,356).
However, according to the inventor's studies, when an olefin is addition-polymerized with the above-mentioned catalyst, its polymerization activity is not completely satisfactory.